Dunn (shoulder) was placed on the 60-day injured list Thursday.
Dunn was traded from the Mariners to the Reds in March and was expected to compete for a spot in the starting rotation, but he'll be forced to miss at least the first two months of the season due to the right shoulder strain that kept him sidelined for most of the 2021 campaign. Luis Castillo (shoulder) and Mike Minor (shoulder) are both on the 10-day injured list to begin the year, so Vladimir Gutierrez, Reiver Sanmartin, Hunter Greene and Nick Lodolo are all beginning the season in the rotation for the Reds.